I had unprotected sex, but with withdrawal. 9 days later, I had my period. I would like to know how likely am I to be pregnant. Given that I haven't had sex since my last period. I've been feeling nausea easily this few days and have been getting back ache easily. I know if I'm about to start a new cycle I would get backache. So I'm not sure if I'm pregnant or just starting my cycle soon.